G1minor
The geomagnetic storm of 17 January 1940
On 17 January 1940 the Kp index reached 5: a G1 (minor) storm, with 3 hours at Kp 5 or more. At its peak the lights could be seen from 280,376 places in the atlas, down to about 51° magnetic latitude.
Kp 5Peak Kp · 17 January 1940 12:00 UT
3Hours at Kp 5 or more
48Largest ap
Solar cycle 17Year 7 of solar cycle 17
Kp every three hours
56789
16 Jan17 Jan18 Jan
Where the lights could be seen
At Kp 5 the lights reach 280,376 places of the atlas on the horizon and 80,365 overhead, down to about 51° magnetic latitude.
The largest towns that could see them
MoscowRussia · 13.3MSaint PetersburgRussia · 5.65MTorontoCanada · 2.79MChicagoUnited States · 2.73MMontrealCanada · 1.9MNovosibirskRussia · 1.64MYekaterinburgRussia · 1.47MKazanRussia · 1.33MCalgaryCanada · 1.31MNizhny NovgorodRussia · 1.2MChelyabinskRussia · 1.18MUfaRussia · 1.14MOmskRussia · 1.1MKrasnoyarskRussia · 1.09MPermRussia · 1.03MOttawaCanada · 1.02MEdmontonCanada · 1.01MStockholmSweden · 985kTyumenRussia · 872kWinnipegCanada · 750kSeattleUnited States · 737kMississaugaCanada · 718kOsloNorway · 718kHelsinkiFinland · 694k